Diquat is also thought to be a neurotoxin, carcinogen and linked to Parkinson's disease. An October analysis of EPA data by the Friends of the Earth non-profit found it is about 200 times more toxic than glyphosate in terms of chronic exposure. [...] The new review of scientific literature in part focuses on the multiple ways in which diquat damages organs and gut bacteria, including by reducing the level of proteins that are key pieces of the gut lining. The weakening can allow toxins and pathogens to move from the stomach into the bloodstream, and trigger inflammation in the intestines and throughout the body. Meanwhile, diquat can inhibit the production of beneficial bacteria that maintain the gut lining. Damage to the lining also inhibits the absorption of nutrients and energy metabolism, the authors said.
The research further scrutinizes how the substance harms the kidneys, lungs and liver. Diquat "causes irreversible structural and functional damage to the kidneys" because it can destroy kidney cells' membranes and interfere with cell signals. The effects on the liver are similar, and the ingredient causes the production of proteins that inflame the organ. Meanwhile, it seems to attack the lungs by triggering inflammation that damages the organ's tissue. More broadly, the inflammation caused by diquat may cause multiple organ dysfunction syndrome, a scenario in which organ systems begin to fail. The authors note that many of the studies are on rodents and more research on low, long-term exposure is needed. The report notes that the EPA is not reviewing the chemical, "and even non-profits that push for tighter pesticide regulations have largely focused their attention elsewhere."
"[T]hat was in part because U.S. pesticide regulations are so weak that advocates are tied up with battles over ingredients like glyphosate, paraquat and chlorpyrifos -- substances that are banned elsewhere but still widely used here. Diquat is 'overshadowed' by those ingredients."